Investing in excellence

As demand for high-quality and precision processed rolled aluminium products steadily expands, the importance of advanced manufacturing technologies is also rising. A state-of-the-art machinery pool is the backbone of efficient and competitive production operations and plays a crucial role in future innovations and sustainable market opportunities. In keeping with this theme, AMAG, as a specialist for surface-critical products, has invested in another new surface treatment line with a highly efficient spray etching system for hot-rolled and cold-rolled coils. The new facility was commissioned this February. The new surface treatment line is a visible sign of the high priority given to surface-sensitive products in AMAG’s product strategy and makes a significant contribution to securing the company’s leading position in this field.

The surface of semi-finished products plays a key role in the end products of many AMAG customers from a wide range of industries. In addition to their outward appearance, it also has an impact on functionality and options for further processing, finishing, and coating. For example, the etching process removes residues, such as oxides that occur during the hot rolling process, and impurities that may be present after cold rolling due to dust, oil, or grease. This results in a cleaner and more even coil surface and largely eliminates visual defects such as uneven surfaces, cracks, or scratch-like damage. The material is thus optimally prepared for further processing steps, such as roller burnishing. In order to minimize the risk of damage to the surface and, depending on the downstream processing step, the coils are either oiled or laminated with foil in-house or at the customer’s premises. In view of the considerable diversity of AMAG’s customer base and associated wide-ranging product portfolio, the layout of the new surface treatment line was optimized to enable rapid product changeovers and thus highly flexible production planning. The design concept also placed a special focus on the gentle production of gloss products by keeping the belt run as simple as possible. Particular care was taken to minimize the number of rollers used for redirection, deoxidation, and building up the belt tension in order to keep the risk of damage as low as possible. This measure benefits not only the particularly sensitive gloss qualities that are used in the architectural sector, as decorative surfaces in consumer electronics, in the cosmetics industry, or as trim parts in the automotive industry, but also all other product groups that are fed through the surface treatment line.

These include braze clad materials, such as those used in manufacturing oil coolers. For products like these, which are vacuum brazed over a large area, the qualitative improvements achieved by the etching step on the surface treatment line lead to more stable processes and lower wastage for the customer. But the etching step is also essential for materials specially developed by AMAG for flux-free controlled atmosphere brazing (CAB). Here, the surface of the brazing layer is subjected to a pickling treatment in order to create a surface with silicon particles while still maintaining low roughness and thus counteracting increased wear on the customer’s sheet metal processing tools.The new line, which can etch thicknesses of up to 5 mm, also marks a change in technology from dipping to spraying, thus ensuring maximum precision and uniformity. In the approximately 50-meter long chemical section of the surface treatment line, a hot alkaline pickling medium (sodium hydroxide solution) is sprayed onto the coil in four zones, which can be controlled as required, using a maximum of around 100 individual nozzles, followed by slightly acidic deoxidation (nitric acid) and subsequent cleaning with water. The coil is then dried with a stream of hot air. There are two options for subjecting the upper and lower sides of the coil to visual checks along the line, which means that surface defects can be identified and eliminated at an early stage.

Another key asset in terms of quality is the advanced digital tool that records all production-related data from the coils. This innovative technology not only helps to optimize quality and productivity, but also contributes to achieving and tracking sustainability goals such as reducing our carbon footprint and media consumption.In line with this, the use of etching and rinsing agents is cascaded to ensure the efficient use of media. The media are also filtered and then reused. Partial wastewater flows are also recycled. As a further bonus in terms of maximizing environmental protection, the process is heated exclusively by electricity.The new surface treatment line is an important step towards ensuring that we can continue to meet the specific requirements arising from a wide range of customer applications and to be able to consistently and reliably deliver top-quality surface finishes in the future. This investment represents a significant step towards increasing efficiency and optimizing quality, which will have a positive impact not only on production processes but also on customer satisfaction.